Observation.  The two latter specimens disagree with Phalangista vulpina in having the spurious molar of relatively smaller size, and the 2nd molar narrower:  the symphysis of the lower jaw is also one line deeper in the fossil.  As the two latter specimens agree in size with the cranium, they probably are all parts of the same species, of which there is no proof that it corresponds with any existing species.  But a comparison of the fossils with the bones of these species (which are much wanted in our osteological collections) is obviously necessary to establish the important fact of the specific difference or otherwise of the extinct Phalanger.

GENUS PHASCOLOMYS.

Sp.  Phascolomys mitchellii, a new species.

(VIII.) Figure 4 Plate 48.  Mutilated cranium.

(VIII.a.) Figure 5 Plate 48.  Part of lower jaw belonging to the above.

(VIII.b.) Figure 6 Plate 48.  Right series of molar teeth in situ.

(VIII.c.) Right ramus of the lower jaw.

Observation.  These remains come nearer to the existing species than do those of any of the preceding genera; but after a minute comparison I find that there is a slight difference in the form of the grinders which, in the fossil, have the antero-posterior diameter greater in proportion than the transverse; the first grinder also is relatively larger, and of a more prismatic form; the upper incisors are less compressed and more prismatic; this difference is so well marked that, once appreciated, anyone might recognise the fossil by an incisor alone.  There is a similar difference in the shape of the lower incisor.  The fossil is also a little larger than the largest wombat’s cranium in the Hunterian Collection.  From these differences I feel no hesitation in considering the species to which these fossils belong as distinct; and propose to call it Phascolomys mitchellii.

NEW GENUS DIPROTODON.

I apply this name to the genus of Mammalia represented by the anterior extremity of the right ramus, lower jaw, with a single large procumbent incisor.

(IX.) Figure 1 Plate 49.  This is the specimen conjectured to have belonged to the Dugong, but the incisor resembles the corresponding tooth of the wombat in its enamelled structure and position.  See Figure 2 Plate 49 and a section of the wombat’s teeth in Figure 7 Plate 48.  But it differs in the quadrilateral figure of its transverse section, in which it corresponds with the inferior incisors of the hippopotamus.

To this, or to some distinct species, of equal size, have belonged the fragments of bones of extremities marked X., X.a., X.b.

GENUS DASYURUS.

Dasyurus laniarius, O. A new species.  I apply this name to the species to which the following remains belong.

(XI.) Figures 3 and 4 Plate 49.  Portions of the left side of the upper jaw.

(XI.a.) Figure 5 Plate 49.  Portions of the left side of the upper jaw.